Apparatus for preventing clogging of oil wells



May 23, 1944- C. c. BANcRoF-r 2,349,536

APPARATUS FOR PREVENTING CLOGGING OF OIL WELLS Filed NOV. 7, 1941 M ,Zgz26 Patented May 23, 1944 APPARATUS FOR PREVENTING CLOGGING F OIL WELLSCharles C. Bancroft, Reno, Nev.

Application November 7, 1941, Serial No. 418,180

2 Claims.

This invention relates to apparatus for preventing clogging ofsubterranean wells, and more particularly to the prevention ofaccumulations of parailin and like asphaltic or bituminous materials inoil wells.

In the operation of oil wells, it has been found that parailn and otherasphaltic or bituminous materials tend to collect on the pump tubing andaround the structure in the lower part of the well. This accumulationbuilds up gradually until the well is substantially closed, so thatproper flow of oil therethrough is seriously interfered with. When thisoccurs, it is necessary to stop production of the Well, and to clean thedeposits therefrom before proper production can be resumed. v

The present invention has for one of its objects the provision ofapparatus for preventing accumulations of such material in a well whichmight interfere with its proper production.

Another object oi.' the invention is to provide for the heating of thepump tubing in the lower part of the well to prevent accumulations ofmaterial thereon.

Still another object of the invention is to provide apparatus forcirculating a heated liquid in heat transferring relationship to thepump tubing of a well to heat the same.

The above and other objects, advantages and novel features of theinvention will be apparent from the following description when read inconnection with the accompanying drawing, in which:

Figure 1 is a diagrammatic view illustrating one installation forpreventing clogging of the well; and

Figure 2 is a similar view of an alternative construction.

As shown in Figure l, an oil well having a casing I0 therein is providedwith a pump tube I2 extending to the bottom thereof and terminating in aperforated or screened portion I4, through which oil from the bearingstrata may enter the pump tube. The tube I2 extends out of the upper endof the well and is provided with suitable pump means, indicatedgenerally at I6. for withdrawing liquid through the tube.

In order to heat the pump tube adjacent the lower part of the well toprevent accumulations of parailin or the like thereon, there isprovided. according to the present invention, a coil I8 of copper tubingor the like, wrapped around the pump tube adjacent the lower part of thewell. If desired, the coil may partially cover the perforated portion I4and may have its turns spaced to permit the iiow of oiltherebetween. Thecoil I8 is preferably formed of relatively small copper tubing and ispermanently installed on the pump tube at the time it is placed in thewell. One end of the coil I8 is connected by a pipe 20 which may be asteel tube with a high pressure storage tank 22 for heated liquid, suchas oil, to be circulated through the coil. It will be noted that thepipe 20 extends into the well between the casing Ill and the pump tubeI2. The opposite end of the coilis connected to a similar tube 24,likewise extending out of the well between the casing and the pump tube.It will be seen from the drawing that the coil is wrapped double with areturn bend at its lower end and with both tubes 20 and 24 connected toits upper end so that a minimum space is required.

Oil to be circulated through the coil is heated in a heater, indicatedat 26, the oil being circulated therethrough by a pump 28 from the lowerpart of a storage tank 30, the heated oil from the heater flowing intothe upper part of the storage tank. From the top of the storage tank,heated oil is withdrawn through a pipe 32 by a high pressure pump 34,and is forced by the pump under high pressure into the high pressurestorage tank 22. A by-pass 36, having a pressure relief valve 38therein, preferably connects the storage tanks 22 and 30 to limit thepressure which can be built up in the storage tank 22. The pipe 24 isconnected to the lower end of the storage tank 30, and may, if desired,be provided with a pressure gauge 40, to indicate the pressure in thereturn line from the well.

In operation, oil heated by the heater is withdrawn from the storagetank 30 by a pump 34, and is forced under high pressure into the tank22. From this tank, it flows through the pipe 20 into the coil I 8 andthrough the coil, thereby heating the pump tube and the adjacent partsin the lower portion of the well to a temperature above the meltingpoint of the paraiiin or other bituminous or asphaltic compounds. Fromthe coil, the oil returns through the pipe 24 to the low pressurestorage tank 30, to be recirculated.

I have found that the oil should be heated to a temperature ofapproximately 400 F., and should be forced into the tubing at a pressureof approximately 2000 pounds per square inch. For the normal well, acirculation of about barrels per day will keep the pump tubing and theadjacent parts at a high enough temperature so that paraiiin and thelike will not accumulate thereon. Thus, by the use of the presentinvention, the well may be kept clear and open indefinitely, therebyeliminating the necessity for periodic cleanings.

Figure 2 illustrates an alternative construction, the parts thereincorresponding to like parts in Figure l being indicated by the samereference numerals.

In this construction, the pump 28 withdraws oil through a pipe I2 fromthe oil storage tank, which may be a tank supplied from the well by thepump I6. This oil is forced through the heater 26 into the low pressurestorage tank 30 and is pumped into the well by the pump 34 through thepipe 20 in the manner described in connection with Figure 1. From thepipe 20, the heated oil flows through the coil I 8 to`heat the pump tubeI2 and the surrounding parts, and returns from the coil through a pipeu, which is tapped into the pipe l2, as shown.

In this construction, it is necessary to provide only one pipe extendinginto the well to conduct heated oil to the coil, the oil aftercirculating through the coil passing into thefpump tube l2 and beingwithdrawn from the well by the main pump I6. Otherwise, the systemoperates in substantially the same manner as that of Figure 1.

While two embodiments of the invention have been shown and described indetail, it will be understood that these are illustrative only, and arenot intended as a. definition of the scope of the invention, referencebeing had for this purpose to the appended claims.

What is claimed is:

l. Apparatus for preventing the clogging of oil weils having pump tubingtherein which comprises a coil of pipe coiled around the lower end ofthe tubing in contact therewith within the Well, an elongated pipe forconducting heated liquid through the well into said coil to heat thetubing, and conduit means to conduct liquid from the coil into saidtubing.

2. Apparatus for preventing the clogging of oil wells having pump tubingtherein which comprises a coil of pipe coiled around the lower end ofthe tubing in contact therewith within the well, an elongated pipe forconducting heated liquid through the well into said coil to heat thetubing, conduit means to conduct liquid from the coil into said tubing,and means above the well for heating liquid, and a pump for forcing theheated liquid through said pipe and coil and into the tubing.

CHARLES C. BANCROFT.

